Gerbera Viridifolia

Characteristics of Gerbera Viridifolia:

Roots thong-like, somewhat fleshy or fusiform, swollen, 1-4 mm wide. Leaves concomitant with or later than the scapes, (3-)5-43.5(-46) cm long, 1.5-10(-12) cm wide, highly variable in length and outline. Petiole (0–)0.5-26 cm long, 1-2(-3) mm wide, up to 10 mm at the very base. Blade 2-23.5(-28) cm long, lanceolate-broadly lanceolate, elliptic, oblong or rarely ovate; apex obtuse or subacute; base often cuneate, sometimes narrowly cordate, rarely truncate or somewhat decurrent as an indistinct wing. Margin ciliate, very variable, narrow leaves being entire or obscurely shallowly lobed, wider ones often irregularly lobed; almost always with rather remote, crenate, distinct teeth in ssp. viridifolia. typically without in ssp. natalensis. Blade fresh green, usually more dull below; young leaves long to very long silky pilose-villose with whitish hairs above, below almost thinly white tomentose and with similar pilose-vil lose hairs as above, later with the upper surface mostly light pilose to somewhat strigose, sometimes even harshly velvety to the touch, more softly pubescent of long pilose and short curled, whitish hairs below, glabrous or almost glabrous when mature; nerves not raised, often densely hairy.

Pappus dirty white to whitish-tawny, rarely somewhat rufous, in ssp. viridifolia from the Natal-Swaziland-Transvaal area (and in 2 collections from Orange Free State near Ficksburg) sometimes violet-purple or violet-purple in the upper, light in the basal part.

Distribution: Gerbera Viridifolia can be found between 350 (in S. Africa) and 3000 m a.s.1. throughout the East African highland from Ethiopia and Southern Sudan through Somalia (fide Wild, 1972), Uganda, Kenya, Malawi, Zaire, Zambia, Rhodesia, Tanzania, and Mozambique to Transvaal, Natal, Swaziland, Orange Free State, Lesotho, and the Eastern Cape as far south as Grahamstown. Also recorded from Cameroun.

Ecology: In open grassland, on savanna or in open Miombo-woodland, in stony soil, on river banks and mountain slopes, along roads etc., from sun to shade, from dry habitats to more or less swamy ground. Common and widespread in highland areas of moderate to high rainfall. Flowering season: Especially flowering in spring after grass fires (small forms), but to be found in its geographical range throughout the year.

Key to the sub-species

1. Roots thong-like, thick. but not swollen; young leaves and scapes moderately pilose-villose of whitish hairs; scapes contemporary with or slightly earlier than leaves. Leaves to 46 cm long, 12 cm wide, scapes to 76 cm long. Occurring throughout the distribution area of the species ssp. viridifolia

Note: Some specimens are difficult to place in either of the subspecies (see below).

Gerbera Viridifolia is a very widespread and highly variable species, although the variation is peculiar in being most noticable in a very small part of the total range, i.e. the Natal-Swaziland-Transvaal area. In this work the species comprizes all specimens of sect. Lasiopus with medium sized heads, rays which are white above, pink or red below, and leaves which are entire and always distinctly greenish below at maturity. The pappus colour is very variable, but the variation is restricted to the same small geographical area as mentioned, while it is always whitish to whitish-tawny (rarely somewhat rufous) in all other areas. From G. galpinii, G. viridifolia is distinguished by its usually broader leaves, which if lanceolate have the lateral veins distinctly visible and the blade at most slightly decurrent, never long decurrent into a wing-like petiole as in G. galpinii. Furthermore the leaves are only glabrous at extreme maturity, and the ray colour is practically never yellow. Some forms of Gerbera Viridifolia ssp. viridifolia approach G. aurantiaca in the problematic area mentioned above, see under G. aurantiaca. Ssp. viridifolia is rather similar to G. ambigua, which has the leaves persistently whitish or lemon tomentose below and yellow rays, except in the same problematic area and the Eastern Cape, where G. ambigua may also have whitelred rays and where forms of ssp. viridifolia and G. ambigua resemble one another (apart from the subsurface-tomentum) and also show much infraspecific variation. The two species have always been treated as distinct until Hilliard (1977) ignored the importance of the lower leaf-surface tomentum and united them under the name G. ambigua, while reestablishing the old SchultzBipontius species G. kraussii for a group of specimens with the leaves densely whitish or lemon tomentose below, nerves raised on the lower surface, petiole winged, and pappus usually violet-purple. This interpretation is not accepted here, but the extreme variation found, and the possibility of hybridization as a complicating factor, have been actualized by Hilliard and deserve much attention.

Hilliard strongly argues that hybridization may play a major role in this ‘complex’, but by maintaining that the leaf tomentum is important to taxonomy, I feel able to easily place almost all specimens within one of the groups having green subsurface or tomentose subsurface. My investigations of material from all over the distribution areas of Gerbera Viridifolia and G. ambigua may disclose facts hitherto hardly realized (see below). I presume that hybridization plays a minor role, if any, but more work on this aspect has to be carried out before this question may be finally settled. Specimens with leaves distinctly greenish below have traditionally been included in Gerbera Viridifolia (= G. abyssinica efr. above), but a few authors have noticed that some specimens deviate from the main group in having swollen, tuberous roots ans scapes developing before the leaves. Schultz-Bipontinus gave this part of the material rank of a distinct species, G. natalensis. The identity of this taxon is discussed below.

Roots thong-like to somewhat fleshy, but not swollen, 1-2(-3) mm wide. Crown of rootstock more or less silky pilose-villose. Leaves in length, form, and hair-covering as described under the species. Scapes 1-4, concomitant with or rarely slightly earlier than the leaves. Otherwise as described under the species. Pappus colour most variable and with a peculiar distribution (see above). Distribution and ecology: As described above Usually a larger plant with broader leaves and heads than ssp. natalensis, but highly variable. The heads may vary more than 1 cm in diameter and the indumentum of the plant is extremely variable, too. In tropical Africa the indumentum is generally weakly developed and the plants have a rather uniform habit, quite small in all vegetative and floral parts. The subspecies was used in hybridization with G. jamesonii before the year 1900, see under that species.

A few specimens in the Natal-Transvaal area are somewhat difficult to place in either Gerbera Viridifolia ssp. viridifolia or in G. ambigua, but many of them are young and in a state when the lower leaf tomentum is disappearing, i.e. belonging to G. viridifolia ssp. viridifolia.

Morphological variation in Gerbera Viridifolia ssp. viridifolia: Previous authors have proposed several new species related to G. viridifolia. However, all these taxa appear only to represent fragments of the whole range of variation, which becomes evident when the total distribution area (represented by 600 collections) is considered.

G. plantaginea represents narrow-leaved forms with a .much tapering base. G. glandulosa represents a form with glandular hairs on the leaves, scape, and/or involucral bracts. None of these characters have any taxonomic value. All intermediate states of leaf-shape are recorded from the entire distribution area. Glandular hairs may be present or absent in G. galpinii and G. ambigua as well, and there is no reason to consider the glandular state as being more than a local variation (most specimens are from Transvaal, but three from Rhodesia and one from Malawi). It does not seem to be correlated with any ecological factor and neither with pappus colour.

G. speciosa represents an intricate problem (see also under G. aurantiaca). The distribution of the taxon is limited to eastern and Central Transvaal and Swaziland, and there are a few somewhat doubtful reports from central and northern Natal; however, some G. viridifolia from East Tropical Africa approaches it, too. The taxon has not been cited since the original description (1927), although Wild (1972) seems to regard it as a synonym of G. viridifolia (Dc.) Schultz-Bip. (cfr. labels on the herbarium sheets).

Morphologically ‘G. speciosa’ appears to be similar to the hybrid G. aurantiaca x G. ambigua (see under G. aurantiaca), but is probably not closely allied to it: (1) Although often similar in general indumentum characters, it never has a white tomentose felt on the lower leaf surface; (2) it has no winged petiole as the hybrid; (3) the heads are generally smaller, as are the rays; (4) the rays do not show such a rich variation in colours as found in the hybrid; (5) finally the distribution is strictly allopatric to that of the hybrid (and G. aurantiaca), the latter only reaching as far north as Vryheid in Natal.

A theory of hybridogenous origin of ‘G. speciosa’ is also tempting in view of its seemingly intermediate position between typical ssp. viridifolia and the ‘G. kraussii form’ of G. ambigua. However, this theory is contradicted by the following: (1) As concluded below, G. ambigua constitutes a definite continuum of forms, while the hypothesis would imply that only ‘G. kraussii forms’ hybridize with G. viridifolia. (2) ‘G. speciosa’ seems perfectly fertile, although admittedly this also seems to be the case in the hybrid G. aurantiaca x G. ambigua. (3) The distribution is very restricted in comparison to those of G. viridifolia ssp. viridifolia and G. ambigua or even the ‘G. kraussii form’. It is unlikely that a hybrid should be found only in such a small part of a widely shared distribution area, where hybridization should be possible almost anywhere, the potential parent species having identical ecology. (4) ‘G. speciosa’ cannot, in its typical form, be separated with certainty from the forms of Gerbera Viridifolia ssp. viridifolia having the pappus tinged more or less violet-purple. Admittedly, the heads of the latter are smaller (about 11-17 mm long, 17-25 mm wide, while typical ‘G. speciosa’ has heads 13-20 mm long, 24-37 mm wide), but otherwise there are no clearcut differences between them. This also goes for the pubescence of the plants and other characters; it is especially interesting that the velvety upper leaf surface typical of ‘G. speciosa’ also can be found in the otherwise typical ssp. viridifolia, mainly in Natal-Swaziland-Transvaal, but sometimes also throughout the rest of the distribution area. To conclude, ‘G. speciosa’ cannot be considered a distinct subunit of the species.

Gerbera Viridifolia ssp. viridifolia must therefore comprise several slightly different genetic forms, as do G. piloselloides and G. ambigua. ‘G. speciosa’ seems to represent a group with rather large heads, a character shared with G. jamesonii and G. aurantiaca, and undoubtedly evolved several times independently in the section, or perhaps representing a basic trait? It is impossible to estimate anything about the size of the heads in the ancestral form of the section; large-headed and smallheaded species occur side by side in many entities of the whole scapose group.

To sum up, the variation of ssp. viridifolia is very great in the Natal-Transvaal area, but much less marked in the much larger distribution area to the north – a variation-pattern strikingly similar to that found in G. Ambigua.

Gerbera viridifolia (DC.) Schultz-Bip. Ssp natalensis

Roots fusiform, the swollen part 2-4 mm wide when pressed. Crown very densely woolly-villose when young, the hairs somewhat to very decaying at maturity. Leaves up to 14 cm long and 3 cm wide, emerging after or only immature during the flowering state. Petiole varying from almost absent to 10 cm long, about 1-2 mm wide, up to 7 mm at the base, long whitish silky-villose when young, later sparsely hairy. Blade 2-9 cm long, from 6 mm wide when immature (on the sheets) to 3 cm wide when mature, lanceolate to elliptic; apex subacute, base cuneate, margin entire or obscurely wavy, rarely remotely denticulate. Both leaf surfaces densely silky hairy with light ciliate to villose hairs, margin heavily ciliate; the indumentum sparser with age, leaving the blade almost glabrous.

Achenes up to 8 mm long, pubescent-pilose, taperingor usually with a beaked part about 2 mm long. Pappus whitish to whitish-tawny.

Note: In the description above only measurements from typical ssp. natalensis sheets have been included.

Distribution: From Baziya Mt. and Ntywenka near Tsolo in the Transkei through Natal to the Transvaal Drakensberg and neighbouring highlands of Swaziland (fide Hilliard 1977: 590). The few specimens collected in the Transvaal are from Volksrust, Iswepe, and Belfast (Lydenburg). A few stunted specimens of ssp. viridifolia are very villose and therefore habitually approaching ssp. natalensis, but the roots are not swollen.

Ecology: Occurring in open grassland, often on slopes, usually in stony ground. Flowering in spring just after fire, mainly from July to October, but a few records are from February to April. Mostly between 300 and 2100m a.s.l., but Medley Wood collected specimens near Durban only 60 m a.s.1.

Ssp. natalensis is typically recognized by the swollen roots and the extremely long villose indumentum of the crown, leaves and scapes; the scapes appear before the leaves, or the plant flowers when the leaves are immature.

Ssp. natalensis is typically smaller than ssp. viridifolia and much less variable.

Schultz-Bipontinus (1844) included G. natalensis in (Eu) Gerbera. Harvey (1865) correctly moved the species to sect. Lasiopus, but reduced it to a synonym of Gerbera Viridifolia. Medley Wood (1912), however, kept G. natalensis as a species, giving an excellent description, and also Dummer (1914) accepted it. Jefferey (1967b) reduced it (and G. abyssinica) to a synonym of G. viridifolia (Dc.) Schultz-Bip., as did Wild (1972). Hilliard (1977) argues against this, emphasizing that G. natalensis is distinct because of: (1) its fusiform (swollen) roots, (2) its long villose indumentum in all parts of young specimens, (3) its scapes appearing before the leaves. No doubt the taxon G. natalensis must be closely related to Gerbera Viridifolia, the main species, and if so what rank should be attributed to it.

The presence of fusiform. tuberous roots seems to be the most important character, unique as it is within the genus. Typically developed, these tubers seem to separate the taxon from Gerbera Viridifolia (Dc.) Schultz-Bip., as do the appearence of the scapes before the leaves, and the characteristical flowering time early in spring after fires. The leaves of ‘G. natalensis’ deviate from those of G. viridifolia in being extremely long villose on both surfaces (at least when young) and with poorly developed crenate teeth. However, the leafcharacters as well as the especially well developed indumentum on petiole and scapes might be explained by considering ‘G. natalens is , an early flowering dwarf form of G. viridifolia. But ‘G. natalensis-forms’ are only found in the critical area of the section, in Natal-Swaziland-Transvaal, and if ‘G. natalensis’ was merely an early flowering form of G. viridifolia, it should be expected to have a much wider distribution.

On the other hand transitional forms are found. Several specimens, especially from Transvaal, are difficult to place in either group. The roots seem to be somewhat swollen, but not tuberous. Likewise, dwarf specimens without swollen roots are found, which in other respects correspond with the typical ‘G. natalensis’, especially in being strongly villose on all parts of the plant. No doubt the very well developed hair-covering is restricted to young or rather young individuals, but this is a general trait in the genus.

It is likely that the typical ssp. viridifolia and ‘G. natalensis’ still are segregating. In the latter, the pappus colour is invariably whitish to whitish-tawny, and nothing really connects it with G. ambigua though it occurs in the critical area, where ssp. viridifolia approaches G. ambigua in several aspects (among these in having partly violet-purple pappus). It must be concluded that ‘G. natalensis’ should be given the rank of subspecies within the limits of G. viridifolia although the two subspecies are sympatric and with no known separating ecological factor. ‘G. natalensis’ certainly is more than just a form of Gerbera Viridifolia, but on the other hand not to be advocated as a distinct species. The ‘wanting’ separating factor between the subspecies may be related to the early flowering time of ssp. Natalensis.